Mixing apparatus having a seal

ABSTRACT

The invention provides a mixing apparatus. The mixing apparatus includes a first container, wherein the first container comprises: a first port; and a mixing chamber. The mixing apparatus further includes a second container, wherein the second container is adapted to receive the first container, and a seal disposed between the first container and the second container. In addition, the mixing apparatus includes a channel between the first port and the mixing chamber, wherein the channel is defined by the seal and the first container. In some examples, the seal includes: a first seal portion; and a transition seal portion, the transition portion comprising: a seal split; and an air intake channel.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a U.S. National Phase application under 35U.S.C. § 371 of International Application No. PCT/EP2018/086041, filedon Dec. 20, 2018, which claims the benefit of European PatentApplication No. 17210903.5, filed on Dec. 28, 2017. These applicationsare hereby incorporated by reference herein.

FIELD OF THE INVENTION

This invention relates to the field of automatic beverage preparation,and more specifically to the field of automatic frothed milk beveragepreparation.

BACKGROUND OF THE INVENTION

Typically, full automatic espresso appliances provide the function ofautomated cappuccino brewing. In most cases, steam is used for heatingand/or frothing the milk, in a similar manner to a barista. To improvethe ease of use of the appliance and provide stable performance to allusers regardless of skill, several milk frothing modules have beendeveloped. Normally, these modules are removable from the baseappliance, so that all parts in contact with milk can be cleaned. Knownsolutions in the field are complex by design and (dis-)assembly can bedifficult.

To be able to open and expose the milk contacting channel for cleaning,the channel may be split. The split channel must be properly sealed inassembled condition to prevent any leakage of the milk to the rest ofthe appliance.

With current seal solutions the seal indentation is strongly related tothe sealing force and may be insufficient in channel portions where thepressure is high, e.g. in a steam transporting channel portion.

There is therefore a need for a milk frothing channel solution that issimple to disassemble and clean, whilst providing adequate sealingacross different portions of the milk frothing channel that aresubjected to various conditions during the milk frothing process.

SUMMARY OF THE INVENTION

The invention is defined by the claims.

According to examples in accordance with an aspect of the invention,there is provided a mixing apparatus comprising:

a first container, wherein the first container comprises:

a first port; and

a mixing chamber for mixing milk with steam and optionally air;

a second container, wherein the second container is adapted to receivethe first container;

a seal disposed between the first container and the second container;and

a channel between the first port and the mixing chamber, wherein thechannel is defined by the seal and the first or second container.

This arrangement allows for milk and steam to be provided to the mixingchamber by way of a channel defined at least in part by a seal. In thisway, the channel may be disassembled for cleaning by simply removing thefirst container from the second container.

In addition, as the channel is itself defined in part by the seal whendisposed between the first and second containers, the adequate sealingof the channel is ensured. Mounting of the two containers togetherprovides the required seal positioning and/or compression or extension.

In an embodiment, the first container comprises a raised containerportion, and wherein the channel is further defined by the raisedcontainer portion.

In this way, the dimensions of the channel may be controlled by alteringthe depth of the raised container portion. The seal, or at least thesurface thereof that helps defining the channel, can in such case besmooth making cleaning thereof very easy.

In a further embodiment, the raised container portion causes anindentation in the seal of greater than 0.2 mm, for example 0.6 mm.

In order to create a sealing force between the seal and the firstcontainer, an indentation is required. By providing an indentation of,for example, 0.6 mm, the area between the first and second containers isreduced, whilst not requiring an excessively high sealing force that maycause deformation of the parts and/or impede proper assembly of thefirst and second containers by a user.

In an arrangement, the seal comprises a raised seal portion, and whereinthe channel is further defined by the raised seal portion.

In this way, the dimensions of the channel may be controlled by alteringthe depth of the raised seal portion. Cleaning required for the firstcontainer may be reduced as the first container may be free of raisedcontainer portions.

In some embodiments, the second container comprises:

a second port; and

a third port, wherein the third port is connected to the mixing chamber,and wherein the channel further connects the second port to the firstport and the mixing chamber.

In this way, it is possible for milk, steam or any other ingredient toenter the channel from outside of the second container. In addition, thethird port allows the contents of the mixing chamber to leave the mixingapparatus without requiring additional extraction from the firstcontainer.

In an embodiment, the seal comprises:

-   -   a first sealing portion;    -   a second sealing portion comprising a first seal port; and    -   a third sealing portion.

The three portions provide sealing of different channel portions andthey may be designed independently although together they may form asingle integral seal element.

In a further embodiment, at least one of the: seal thickness; seal widthand shore hardness of the first, second or third sealing portions may bedetermined independently of the other sealing portions.

In this way, it is possible to tune various portions of the sealaccording to the conditions those portions are exposed to. For example,a sealing portion that is exposed to high pressure may have a largerseal thickness than a sealing portion exposed to normal pressures. As afurther example, for a sealing portion when the channel dimensions areparticularly important, the seal hardness may be higher than for asealing portion where the channel dimensions are less critical.

In an arrangement, the seal comprises a span seal. A span seal is a sealwhich is extended across and beyond an opening and thus acts down overthe opening in the manner of a closing lid. Thus it spans the full areaof the opening to be sealed rather than forming a seal around a separateclosure part. The term “span seal” is used to denote this general typeof sealing configuration.

The span seal operates using pull forces, which stretch the seal ratherthan compress it. This results in a slow rising indentation force, whichmeans manufacturing tolerances in the various parts are easier toovercome without adding a lot of useless force. The span seal providessealing direct to the channel without a large amount of deformationmaking the geometry of the channels easier to control.

In some arrangements, the span width of the sealing portions may bedetermined independently of the other sealing portions.

By controlling the span width of the span seal, it is possible tofurther control the sealing force and indentation of the seal.

In an embodiment, the channel comprises:

a first channel portion, wherein the first channel portion is defined bythe first sealing portion and the first container and is connected tothe first port;

a second channel portion connected to the first channel portion, whereinthe second channel portion is defined by the second sealing portion andthe first container; and

a third channel portion connected to the first and second channelportions and the mixing chamber, wherein the third channel portion isdefined by the third sealing portion and the first container.

In a further embodiment, the second channel portion is adapted toreceive steam by way of the first seal port.

In this way, steam may be provided to the channel from outside of thesecond container without compromising the sealing of the seal.

In further or other embodiments, the first channel portion is adapted toreceive milk by way of the first port.

In this way, milk may be stored in the first container and provided fromthe first container to the channel without compromising the sealing.

In yet further or other embodiments, the third channel portion isadapted to receive input from the first and second channel portion andwherein the third channel is adapted to impart a Venturi effect on thereceived input.

In this way, the contents of the mixing chamber are prevented fromflowing back into the channel due to the pressure difference caused bythe third channel portion.

In an arrangement, the shore hardness of the seal is in the range 30 to60, for example 40 to 45 (based on the shore hardness scale A).

In this way, the deformation of the seal over a range of pressures willbe reduced.

According to examples in accordance with an aspect of the invention,there is provided a mixing apparatus comprising:

a first container comprising a mixing chamber for mixing milk with steamand/or air;

a second container, adapted to receive the first container andcomprising a third port that in assembled condition is connected to themixing chamber;

a seal disposed between the first container and the second container,wherein the seal comprises:

a first sealing member disposed between the mixing chamber and the thirdport; and

a transition seal portion, the transition seal portion comprising:

-   -   a seal split; and    -   an air intake channel; and

a channel connected to the mixing chamber and the seal split, whereinthe channel is defined by the first or second container and thetransition seal portion. This arrangement provides a first sealingmember between the mixing chamber of the first container and the thirdport of the second container, whilst also providing a transition sealportion thereby allowing milk, steam or other such ingredients to enterthe mixing chamber without compromising the sealing of the apparatus.

Typically, a simple seal split would present a vulnerability in thesealing of the apparatus as the seal does not fully surround the mixingchamber; however, the air intake allows air to be drawn through the sealsplit and into the mixing chamber. In this way, ingredients entering themixing chamber are prevented from leaking through the seal split of thetransition portion of the seal.

In an embodiment, the air intake channel defines an air flow from theair surrounding the mixing apparatus to the mixing chamber.

In this way, the air intake may draw air in from the surroundingenvironment using the negative pressure caused by the ingredientsflowing from the channel to the mixing chamber.

In a further embodiment, the air intake imparts a Venturi effect on theair flow. In this way, the ingredients are prevented from leaving thechannel through the air intake due to the pressure difference betweenthe channel and the air intake.

In an arrangement, the first sealing member comprises a radial seal.

In this way, it is possible to seal the outer edges of the mixingchamber without interrupting the flow of the contents of the mixingchamber to the third port of the second container.

The seal may further comprise a first sealing portion which defines amilk introduction passageway.

There may also be a second sealing portion which comprises a first sealport for the introduction of steam.

The transition seal portion may be disposed between the first sealingmember and the second sealing portion.

The first container may further comprise a first port and wherein thechannel, in particular the milk introduction passageway thereof furtherconnects the first port to the mixing chamber. The channel may bedefined by the transition seal portion, the first and second sealingportions and the first container.

The first and second sealing portions preferably comprise span sealswhereas the first sealing member is a radial seal.

In this way, it is possible to seal both the mixing chamber and thechannel system described above using a single integrated seal. Thisfurther reduces the complexity of disassembling the apparatus forcleaning as only one seal requires cleaning for both the channel and themixing chamber.

At least one of the: span seal thickness, shore hardness and span widthof the first and second sealing portions may be different to each other.

In this way, it is possible to tune the first and second sealingportions according to the conditions those portions are exposed to, asdescribed earlier.

The transition seal portion may further allow a transition between twoseal types, thereby enabling the most appropriate seal type to be useddepending on the area being sealed. For example, the transition portionmay allow for a span seal over the channel and a radial seal around themixing chamber to be integrated into the same seal.

According to examples in accordance with an aspect of the invention,there is provided a coffee maker, the coffee maker comprising;

a liquid coffee extraction apparatus; and

the mixing apparatus as described above.

BRIEF DESCRIPTION OF THE DRAWINGS

Examples of the invention will now be described in detail with referenceto the accompanying drawings, in which:

FIG. 1A shows an exploded view of an example mixing apparatus;

FIG. 1B shows an assembled view of the mixing apparatus of FIG. 1A;

FIG. 2A shows a detailed view of the channel of the mixing apparatus ofFIG. 1A;

FIG. 2B shows the flow of fluid through the channel of FIG. 2A;

FIG. 3A shows an example seal;

FIG. 3B illustrates the operation of the span seal of FIG. 3A;

FIG. 4A shows an alternative channel of a mixing apparatus;

FIG. 4B shows a cross section of the channel of FIG. 3A;

FIG. 5 shows a graph of indentation against seal pressure for a spanseal and a compression seal;

FIG. 6 shows a graph of indentation against seal pressure for differentportions of the seal;

FIG. 7 shows an example transition portion of a seal;

FIG. 8 shows the channel for the design of FIG. 2A in more detail; and

FIG. 9 shows a perspective view in cross section of the top end of thechannel.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The invention provides a mixing apparatus. The mixing apparatus includesa first container, wherein the first container comprises: a first port;and a mixing chamber. The mixing apparatus further includes a secondcontainer, wherein the second container is adapted to receive the firstcontainer, and a seal disposed between the first container and thesecond container. In addition, the mixing apparatus includes a channelbetween the first port and the mixing chamber. The channel is defined bythe seal and the first or second container.

In some examples, the seal includes: a first seal portion; and atransition seal portion, the transition portion comprising: a sealsplit; and an air intake channel.

FIG. 1A shows a mixing apparatus 100 comprising: a first container 110;a second container 120, adapted to receive the first container; and aseal 130 disposed between the first and second containers.

The seal is for example a press fit into a side wall of one of the twocontainers so that when the two containers are assembled, the seal issandwiched between them. The mating between the seal and one of thecontainers forms a closed channel which defines fluid paths for a milkinlet, a steam inlet and optionally an air inlet. By separating the twocontainers all parts can be easily cleaned. There is only one sealelement for defining all the channels used for the supply and mixing ofmilk with steam and/or air.

The seal may be 2 shot (2K) molded into the first or second container,or else it may be a separate seal which is removable from a recess inthe first or second container.

The mixing apparatus further comprises a channel 140, which is definedby the seal 130 and the first container 110 when the mixing apparatus isassembled. In the example shown in FIG. 1 , the first container 110comprises a raised channel portion 145, which further defines thechannel. The channel connects a first port 150 at the bottom of thechannel and a mixing chamber 160 at the top of the channel. In addition,the second container 120 comprises a second port (not visible in FIG.1A) connected to a first seal port 170 of the seal, wherein the channelfurther connects the first seal port 170 to the first port and themixing chamber.

FIG. 1B shows the mixing apparatus 100 of FIG. 1A in an assembled state.

In this Figure, it can be clearly seen that the second container 120further comprises a second port 175 from which steam is provided to thefirst seal port 170, and a third port 180 connected to the mixingchamber 160 of the first container 110, thereby allowing the contents ofthe mixing chamber to be easily obtained from the mixing apparatus 100.The operation of the mixing apparatus is described with reference toFIG. 2A below.

FIG. 2A shows a detailed view 200 of the channel 140 of the mixingapparatus of FIG. 1A.

The channel 140 may be divided into several portions according to theoperation performed by each portion. In operation, milk may be providedto the first container 110 and steam may be provided to the first sealport 170. As steam enters the channel 140, milk is drawn from the firstcontainer 110 into a first channel portion 210 by way of the first port150. The steam enters a second channel portion 220 and travels through athird channel portion 230 and into the mixing chamber 160, the flow ofsteam generating a negative pressure in the first channel portion 210,thereby drawing the milk along the first channel portion.

The milk is drawn along the first channel portion 210 until it meets theintersection of the three channel portions, where the flow of steamdraws the milk and steam into the third channel portion 230 whichterminates at an end 235 which opens into the mixing chamber 160. Thethird channel portion may be adapted to impart a Venturi effect on themilk and steam as they pass through the third channel portion.

The steam is used to heat the milk and it operates the Venturi (i.e. areduced pressure) to suck the milk up the first channel portion 210.

Air may be introduced at the end point 235, by suction due to the flowspeed. For this reason, the arrangement doesn't leak. The air introducedprovides bubbles for the desired frothing.

The Venturi effect may be achieved by simply restricting the crosssectional area of the third channel portion 230 relative to the first210 and second 220 channel portions. The increase in speed of the milkand steam as they enter the third channel portion in combination withthe drawing in of air defines the frothing performance of the mixingapparatus, and the pressure differential prevents the milk and steamfrom flowing down the incorrect channels.

The first channel portion 210 is typically vertical in use and extendsup from the (milk entry) first port 150. At the top it meets the secondchannel portion 220 to one side which has a steam entry port 170 at itsremote end, and it meets the third channel portion 230 to the otherside, which has the mixing chamber 160 at its remote end. The channel140 may thus have a T-shape, and the seal 130 may have a correspondingT-shape.

The seal 130 is for example an integral part of the second container120. It may alternatively be a removable seal, in which case it may be apress fit into a side wall of the second container 120. In someinstances, the seal 130 comprises a first sealing member 240 comprisingtransition portion 250. These will be described in more detail withreference to FIGS. 7 and 8 .

FIG. 2B shows a simple illustration of the intersection of the threechannel portions.

As described above, the milk 215 flows along the first channel portion210 due to the negative pressure generated by the steam 225 flowing fromthe second channel portion 220 to the third channel portion 230. As canbe seen from the Figure, the channel widths are reduced as the milk andsteam enter the third channel portion, thereby imparting a Venturieffect on the milk and steam flows, which is used to draw the milk alongits channel.

Air may be drawn in at the end 235 of the third channel portion 230 sothat there is a milk, steam and air mixture entering the mixing chamber160. The aim of the mixing chamber is to release large bubbles andretain only small air bubbles in the mixture. The air, milk and steammixture forms the fluid that enters the mixing chamber.

FIG. 3A shows the seal 130 of FIG. 2A in more detail.

It is clear from the above passage relating to FIG. 2A that the variouschannel portions undergo a variety of different conditions when themixing apparatus 100 is in operation. Thus, as each seal area has theirown specification, the seal, in this case a span seal, can be optimisedfor each area without risk of leakage in the transition areas.

There are three parameters that may be adjusted to tune the sealingforce of the span seal. The three parameters are: the shore hardness ofthe seal; the span width of the seal, which increases the sealing forcebut may also introduce some deformation to the channel; and thethickness of the seal. As the various areas of the span seal may betuned using the span width and seal thickness, the risk of leakage islargely reduced as the need for transitions between different seals iseliminated.

For example, the seal may comprise a first sealing portion 310 forsealing the first channel portion 210 of the channel. Thus, the firstsealing portion 310 should be adapted to withstand the negative pressurepresent in the first channel portion 210. As this pressure is typicallylow, for example, around −0.15 bar, the required sealing force is low;however, the first channel portion 210 may be relatively long, forexample 200 mm, meaning that the required sealing force increases. Asthe milk is low temperature at this stage and the dimensions of thefirst channel portion 210 are not critical to the milk frothing process,the sealing force of the first sealing portion 310 may be increased bysimply increasing the span width.

As a further example, the seal 130 may comprise a second sealing portion320 for sealing the second channel portion 220 of the channel 140. Inthis case, the second sealing portion 320 must withstand both the highpressure, for example 1 bar, and the high temperature, for example 105°,of the steam entering the channel. As with the first channel portion210, the geometry of the second channel portion 220 is not critical tothe milk frothing process meaning that the span width of the secondsealing portion 320 may be increased to increase the sealing force andthe seal thickness may be increased to increase both the sealing forceof the second sealing portion and the resistance of the second sealingportion to the high temperature of the steam.

As a final example, the seal 130 may comprise a third sealing portion330 for sealing the third channel portion 230 of the channel. Thedimensions of the third channel portion 230 are critical to theperformance of the milk frothing process and the tolerance fordeformation is low, for example ±0.1 mm. Therefore, the span width ofthe third sealing portion 330 may not be freely increased and sealthickness delivers only marginal benefit to the sealing force itself. Inthis case, the shore hardness of the seal provides the required sealingforce. The shore hardness of the seal may be constant, for example 45shore, throughout the seal in order to prevent excessive span widths andseal thicknesses in the first and second sealing portions 310, resp.320. In addition to the milk frothing process, the seal 130 would berequired to withstand daily cleaning, typically by way of a dishwasher.In this case, the shore hardness of the seal may help to extend thelifetime of the seal.

Finally, the illustrated seal 130 has the first sealing member 240 whichprovides a radial seal around the mixing chamber 160. The three sealingportions 310, 320, 330 are span seals whereas the first sealing member240 is a radial seal. A span seal cannot be used to seal the mixingchamber 160 because an opening is needed from the mixing chamber 160 tothe third port 180. The three sealing portions 310, 320, 330 and thefirst sealing member 240 may together form a single integratedcomponent.

FIG. 3B illustrates the operation of a span seal acting as the seal 130.

The span seal works on pull forces, F_(P), which stretch the seal overthe channel 140 instead of compressing it. The span seal providessealing directly onto the channel without a large amount of deformation.The channel 140 cross section dimension and shape is independent of theindentation and sealing force leading to a more stable milk frothperformance, particularly in the third sealing portion 330. Theindentation of the span seal may be, for example, 0.6 mm. The spanwidth, S, of a span seal is defined as:

${S = {y - \frac{x}{2}}},$

where y is the distance from the centre of the channel 140 to the edgeof the span seal 130 and x is the width of the channel.

FIGS. 4A and 4B show a detailed view of an alternative channelarrangement 400.

In this case, the seal 410 comprises a raised seal portion 415, whichdefine the channel 420 in combination with the first container 110. Thisarrangement may simplify the cleaning of the first container 110 asthere are fewer raised portions in which the ingredients may get stuck.In this case, the shore hardness of the seal would need to be furtherincreased in order to ensure that the raised seal portion 415 does notdeform under high pressure, thereby causing leakage to occur.

FIG. 5 shows a graph 500 of required seal pressure, N/mm, againstindentation, mm, for a span seal (plot 510) and a compression seal (plot520). The seal pressure was measured for a seal length of 250 mm at ashore hardness of 60 shore, with a nominal indentation of 0.6 mm asshown by the dotted line.

As can be seen from the graph, the required seal pressure for thecompression seal 520 rises far quicker than for the span seal 510 inorder to reach the same indentation. From the graph, the required sealpressure for an indentation of 0.6 mm on the compression seal is 2.1N/mm. This leads to a total seal force of 2.1 N*250 mm=575 N. A sealforce of 575 N may cause considerable deformation of the components ofthe mixing apparatus and a situation in which a user may not be able toproperly assemble the mixing apparatus. In this case, lowering the shorehardness of the seal would not decrease the sealing force enough.

Looking to the span seal of plot 510, an indentation of 0.6 mm requires0.2 N/mm seal pressure. This leads to a sealing force of 0.2 N*250 mm=50N. Whilst a sealing force of 50 N is still high, by lowering the shorehardness it may be brought into an acceptable range.

FIG. 6 shows a graph of seal pressure, N/mm, against indentation, mm,for the first sealing portion (plot 610) and second sealing portion(plot 620) of a span seal, of shore hardness 45 shore, acting as theseal 130.

In this case, the span width of the first and third sealing portions is3.1 mm and the seal thickness is 2 mm; whereas the span width of thesecond sealing portion is 2.1 mm and the seal thickness is 3 mm. As canbe seen from the graph, for an indentation of 0.6 mm across the entireseal, the seal pressure is well below 0.25 N/mm, which is withinacceptable levels of sealing force for use in the mixing apparatus.

FIG. 7 shows a seal 700 having a first sealing member 240, which in thiscase is a radial seal, and a transition portion 250 as previouslyillustrated in FIG. 2A. A view from above is shown in the top image anda perspective view of the opposite container 110 is shown in the bottomimage.

The transition portion 250 comprises a seal split 720 to facilitate themovement of milk and steam from the channel defined by the other sealingportions 710 (equivalent to 310, 320 and 330 in FIG. 3A), which in thiscase is the set of span seals as described above, into the mixingchamber. In this way, it is possible to integrate both the span sealsand the radial seal into a single seal, thereby increasing thesimplicity of the mixing apparatus for disassembly and cleaning.

Performing a straight combination of a radial and span seal willtypically cause leakage in the transition area due to the seal split.

As seen more clearly in the bottom image of FIG. 7 (and in FIG. 2A aswell), the channel 140 in this example is defined by raised portions 145of the first container 110. The raised portions define the sides of theflow channels where span seals are to be applied. At the seal splitthere is a gap 725 in the side wall which allows external communicationto the end 235 of the third channel portion 230 (as shown in FIG. 2A).The gap 725 opens into the space between the first and second containers110, 120.

FIG. 8 shows the channel (for the design of FIG. 2A) in more detail.

The seal is again fitted to the second container 120 and the raisedridges are formed on the first container 110 as shown in FIG. 8 .

The gap 725 for allowing the intake of air in this example is providedonly on one side of the third channel portion 230. Only the top side(i.e. the side facing away from the first port 150) is open. The gap 725comprises an omitted section of the raised portions which defines thethird channel portion 230. The omitted section may for instance have alength in the range of 1.5 to 5 mm.

FIG. 9 shows a perspective view in cross section (the cross section isidentified in FIG. 7 ). FIG. 9 shows the closed base 161 for the innerpart of the mixing chamber 160. It shows the second and third channelportions 220, resp. 230 and the gap 725 in the raised portion at the end235 of the third channel portion 230, which functions as the air inlet.It shows the seal 130 as an integral part of the second container 120.

An air inlet is formed by the gap 725. This defined transition portion250 can be achieved through a controlled combination of the seal 720split and Venturi of the milk froth system. In this area no sealing isallowed, as ambient air must be sucked in. By providing the air inlet inline with the channel system at the transition portion 250 of the seal130, the sealing area is controlled as the air drawn in by the flowwithin the channel prevents uncontrolled leakage of milk.

The speed of the liquid (milk, steam and air) entering the mixingchamber 160 is important for the foam quality. It is preferred that theair enters at the end 235 of the third channel portion 230. There is aminimum hole size such as formed by a 1.5 mm gap. The distance betweenthe milk Venturi and the air gap, and the distance between the air gapand the mixing chamber 160 are the key parameters for defining the milkfrothing characteristics.

Other variations to the disclosed embodiments can be understood andeffected by those skilled in the art in practicing the claimedinvention, from a study of the drawings, the disclosure, and theappended claims. In the claims, the word “comprising” does not excludeother elements or steps, and the indefinite article “a” or “an” does notexclude a plurality. The mere fact that certain measures are recited inmutually different dependent claims does not indicate that a combinationof these measures cannot be used to advantage. Any reference signs inthe claims should not be construed as limiting the scope.

The invention claimed is:
 1. A mixing apparatus, comprising: a firstcontainer, wherein the first container comprises: a first port, whereinthe first port is configured to draw milk from the first container; anda mixing chamber for mixing the milk with steam and/or air; a secondcontainer, wherein the second container is adapted to receive the firstcontainer; a seal disposed between the first container and the secondcontainer; and a channel between the first port and the mixing chamber,wherein the channel is formed by the seal being disposed between thefirst and second containers.
 2. The mixing apparatus of claim 1, whereinthe first container comprises a raised container portion, and whereinthe channel is defined by the raised container portion.
 3. The mixingapparatus of claim 2, wherein the raised container portion causes anindentation in the seal of greater than 0.2 mm.
 4. The mixing apparatusof claim 1, wherein the seal comprises a raised seal portion, andwherein the channel is defined by the raised seal portion.
 5. The mixingapparatus of claim 1, wherein the second container comprises: a secondport; and a third port, wherein the third port in assembled condition isconnected to the mixing chamber, and wherein the channel furtherconnects the second port to the first port and the mixing chamber. 6.The mixing apparatus of claim 1, wherein the seal comprises: a firstsealing portion; a second sealing portion comprising a first seal port;and a third sealing portion.
 7. The mixing apparatus of claim 6, whereinat least one of a: seal thickness, seal width, and shore hardness of thefirst, second, or third sealing portions are different to acorresponding parameter of an other sealing portion of the first,second, or third sealing portions.
 8. The mixing apparatus of claim 6,wherein the channel comprises: a first channel portion, wherein thefirst channel portion is defined by the first sealing portion and thefirst container, and wherein the first channel portion is connected tothe first port; a second channel portion connected to the first channelportion, wherein the second channel portion is defined by the secondsealing portion and the first container; and a third channel portionconnected to the first and second channel portions and the mixingchamber, wherein the third channel portion is defined by the thirdsealing portion and the first container.
 9. The mixing apparatus ofclaim 8, wherein the first channel portion is adapted to receive milk byway of the first port.
 10. The mixing apparatus of claim 8, wherein thesecond channel portion is adapted to receive steam by way of the firstseal port.
 11. The mixing apparatus of claim 8, wherein the thirdchannel portion is adapted to receive input from the first and secondchannel portions, and wherein the third channel portion is adapted toimpart a Venturi effect on the received input.
 12. The mixing apparatusof claim 6, wherein the seal comprises a span seal.
 13. The mixingapparatus of claim 12, wherein a span width of the first, second, andthird sealing portions are different to each other.
 14. The mixingapparatus of claim 1, wherein a shore hardness of the seal is in therange of 30 to 60 shore.
 15. A coffee maker, the coffee makercomprising: a liquid coffee extraction apparatus; and the mixingapparatus of claim
 1. 16. The mixing apparatus of claim 2, wherein theraised container portion causes an indentation in the seal of greaterthan 0.5 mm.
 17. A mixing apparatus, comprising: a container, whereinthe container comprises: a port configured to draw milk from thecontainer; and a mixing chamber for mixing the milk with steam and/orair; a seal; and a channel between the port and the mixing chamber,wherein the channel is formed by the seal and the container.
 18. Amixing apparatus, comprising: a first container, wherein the firstcontainer comprises: a first port; and a mixing chamber for mixing milkwith steam and/or air; a second container, wherein the second containeris adapted to receive the first container; a span seal disposed betweenthe first container and the second container; and a channel between thefirst port and the mixing chamber, wherein the channel is formed by thespan seal spanning over the complete channel area, and being disposedbetween the first and second containers.